Dear Mr Andrew,
Thank you for your letter of 15 June 2026 regarding the transparency and presentation of statistics on the NHS waiting list for elective treatment, produced by NHS England. These are known as ‘referral to treatment’ (RTT) statistics. In your letter, you set out concerns that have been raised in Written Parliamentary Questions and Commons exchanges. The letter is accompanied by an annex showing the information that parliamentarians have sought on elective waiting lists.
You asked whether the current statistics give the UK Parliament, patients and the public a sufficiently clear picture of what is happening with the NHS waiting list, including whether they distinguish clearly between patients who are treated and those who are removed from waiting lists without treatment, whether patients are added back onto waiting lists after removal, and whether changes in referral pathways affect the statistics’ comparability over time.
On these points, my view is that the current published statistics provide important information on the size, activity and overall trends of waiting lists, but only partially meet these more detailed information needs at present. In particular, the statistics do not yet clearly distinguish between patients who have been treated and those who are removed without treatment; they do not identify whether patients who are removed are subsequently re-added to a waiting list; and they provide limited information on how changes in referral pathways and recording practices affect comparability over time.
It is important to note that the RTT statistics are designed to measure patient pathways (the total time from a GP referral to the start of consultant-led treatment). A single patient may have more than one referral pathway open at the same time, for example where they are waiting for treatment for more than one condition. As a result, counts of pathways do not correspond directly to the number of individual people waiting for care, and should not be interpreted as such. This distinction is important when considering questions about removals, outcomes and re-additions, which cannot be directly tracked at patient level within the aggregate published statistics.
These statistics were originally developed to monitor performance against the 18‑week referral to treatment standard. They provide an aggregate view of waiting times and pathway completions and remain central to assessing NHS performance. However, the issues that you and other parliamentarians have raised reflect a broader shift in user need. Users increasingly want to understand not only how many pathways are waiting, but also what is driving changes in the waiting list, which may influence the published figures. At present, the statistics do not fully support this deeper understanding, which is why continued development remains important.
In March 2026, the Office for Statistics Regulation (OSR) completed a compliance review of NHS England’s referral to treatment (RTT) statistics. We concluded that the statistics continue to meet the standards of the Code of Practice for Statistics, while identifying where further developments would enhance their trustworthiness, quality and value. These include improving transparency and user understanding of unreported removals and pathway closures, strengthening the accessibility and coherence of guidance and outputs, taking a more proactive approach to user engagement, and providing clearer information to support appropriate interpretation and comparability of the statistics over time.
Since we published this review, NHS England has taken positive steps to improve the transparency and interpretability of the statistics. These include publishing additional guidance on unreported removals and introducing a national time series showing the scale of these removals over time, improving transparency in line with a recommendation from our review. NHS England has also initiated a programme of work to improve data quality for unreported removals, involving regional teams and providers across the NHS. A high number of unreported removals can limit understanding of the reasons patients leave waiting lists and reduce transparency about factors affecting waiting list numbers. This work aims to improve the completeness and timeliness of reporting, identify the causes of unreported removals, and support further improvements to data quality and reporting practices.
Alongside this work, NHS England continues to develop its RTT data and Waiting List Minimum Data Set (WLMDS) dashboards to improve accessibility and user understanding. Recent publications have also incorporated estimates for missing provider data and indicative estimates of the number of unique patients alongside pathway counts. Together, these developments can help users better understand how activity flows through the RTT system, clarify the distinction between pathways and people, and support a more informed interpretation of changes in waiting list volumes.
One of the principal concerns that you raised in your letter is understanding why pathways are closed and how these closures impact the changing NHS waiting lists over time. We also identified this as a key issue identified in our compliance review. As part of developing and improving the waiting times statistics, we consider that NHS England and the Department of Health and Social Care should be more open about why pathways end and should publish additional information about this in the Waiting List Minimum Data Set (WLMDS) in the future.
More broadly, we have highlighted in a recent public statement the importance of careful interpretation of NHS waiting time statistics, including the need to distinguish between pathways and people, and to recognise that these statistics reflect flows through the system rather than a simple count of individuals. Supporting clear and consistent use of these statistics is important to ensure that they inform public debate effectively.
The annex to your letter highlights a sustained interest from parliamentarians in understanding these issues in greater detail. In our view, this reinforces how important it is for NHS England to develop the statistics in a way that supports both performance monitoring and a clearer understanding of the drivers of change.
In summary, NHS England’s statistics on elective waiting times remain crucial for understanding waiting list activity and performance. NHS England has made encouraging progress in improving the statistics’ accessibility, transparency and interpretability. This work has included developments that address several of the areas highlighted in our compliance review. However, the concerns raised in Parliament highlight that there remains a gap between the information currently available and users’ needs.
While ongoing development work is encouraging, the challenge is not simply to increase the volume of information published, but to support meaningful interpretation of the statistics. Users increasingly require a clearer understanding of what is driving changes in waiting list numbers, including the factors affecting both additions to and removals from the list. Alongside continuing improvements to the underlying data, we encourage NHS England to consider how it can further support users by providing clearer explanations of the factors influencing waiting list trends and what the statistics can and cannot tell users about changes over time. We consider this an important area for further improvement.
OSR will continue to engage with NHS England and monitor its progress against the recommendations from our compliance review. We anticipate a public update from NHS England by August 2026. We will continue to encourage improvements that help users better understand and interpret the factors driving changes in waiting lists and ensure that the statistics remain of high quality and are transparent and informative.
Thank you again for raising these important issues with us. I would also be very happy to meet with you to discuss these matters further and to hear more about the concerns that have been raised by parliamentarians regarding the interpretation and transparency of NHS waiting list statistics.
Yours sincerely,
Ed Humpherson
Director General for OSR
Related links: Statement: Understanding NHS planned care waiting times statistics across the UK – Office for Statistics Regulation